Question

A dilute solution of KCl was placed between two Pt electrodes 10.0 cm apart, cross which a potential difference of 6.0 volt was applied. $K^{+}$ ions move $x$ cm in 2 hour at ${25}^{o}C$, then $x$ is__________. (nearest integer)
Ionic conductivity of $K^{+}$ at infinite dilution is $73.52Sc{m}^{2}mo{l}^{-1}$ at ${25}^{o}C$. (Write your answer to the nearest integer)

Answer 1

${\lambda }_{K^{+}}^{\infty }=73.52$
Ionic mobility $u_{K^{+}}^{\infty }=\frac{{\lambda }_{K^{+}}^{\infty }}{F}=\frac{73.52}{96500}$

$=7.619\times {10}^{-14}c{m}^{2}se{c}^{-1}vol{t}^{-1}$

Potential gradient applied $=\frac{6.0}{10}=0.6voltc{m}^{-1}$

$\therefore$ Speed of $K^{+}=$ Ionic mobility $\times$ pot. gradient
$=7.619\times {10}^{-4}\times 0.6cmse{c}^{-1}$

$=45.714\times {10}^{-5}cmse{c}^{-1}$

$\therefore$ Distance travelled by $K^{+}$ in 2 hour
$=45.714\times {10}^{-5}\times 2\times 60\times 60=3.292cm$